It is known that windspeed can be determined by transmitting a laser pulse into the wind and measuring the Doppler frequency shift of the light backscattered from aerosols and particles moving with the wind. The velocity of the wind V.sub.W in the direction of the laser pulse is: ##EQU1## where f.sub.s is the Doppler frequency shift and .lambda. is the wavelength of the laser pulse. Four proposed windspeed detection systems are discussed by Menzies in "Doppler Lidar Atmospheric Wind Sensors: A Comparative Performance Evaluation for Global Measurement Applications from Earth Orbit"; Applied Optics, Vol. 25, No. 15, Aug. 1, 1986. The principle challenge inherent in these systems is isolating the laser backscatter signal from background noise. These proposed systems utilize either a heterodyne detection system or a Fabry-Perot filter.